left handed rope thread

[GeorgN]

Hi guys!

This is my first post here and I hope you can help me out. First I`d like to introduce you our lathe. It`s Gildemeister NEF400 ( http://www.gildemeister.com/en,turni...d?opendocument ) with Heidenhein control.
Part what I need to make contains inside left handed rope thread into aluminium detail ( I saved pdf. file of drawing to attachment )
Can you give me some advice, how and can I even make it? What tool you recomend to use ( we use mostly Mitsubishi or Sandvik tools and inserts )

Thanks to everyone!
Georg

[rottenmachinist]

How many pieces are you going to run? You could use something like a sandvik coroturn 111 screw clamp. The lead, pitch, taper, major dia., minor dia. and single depth are all there.
Looks like you will be making some impressions soon. Do you have a optical comparator or cmm? Looks like a fun one! We do lots of threads so I know your pain.

Good luck!

[rottenmachinist]

I see what you 1st problem is. IT'S METRIC! Just kidding. Here is a pic of the tool I was talking about.

[GeorgN]

Thanks "rottenmachinist" But this tool is basicly boring bar? We have such a ones....but question is that how to make thread with this 30 degree insert? Do you make thread cutting program but just use this tool and insert?

[rottenmachinist]

Hey, sandvik has a .197 dia., which would be 5mm round insert. it's smaller than your thread radius. You should see if they have a tool for the id that uses that insert. then program the thread to center cut. Might be worth looking into. Are you going to use a lathe or a mill?

[TonyAllen]

Hi Georg
Nice machine , Make sure U have option for tapered threads as these are 3 degrees included .. or will U program this Off line with Mastercam or other cad / cam ? ..
First I would Bore the hole 60 deep Trig. the small end as this dim. in not given
second I would make a profile insert 12.7 wide ...It is only 1.5 mm deep
I would take .2 deep cuts on the test and work up from their
now for the profile of that insert the R 5.5 and the R6 are both on 12.7 pitch
I am going to refer to the 6 mm as the vally and the 5.5 mm as the Mountain
so make the insert with the R 6mm in the middle and half of the mountain on the left and half the mountain on the right ....U will need more info on the print as they didnot say how wide either radius is .. best guess is the 6 is 7.2 wide and the 5.5 would be 2.75 wide on left side and right side.

Ok I am sure i am confusing U but now remember that the Vally on the part is the Mountain on the tool ...and remember that you have Left hand threads
This is a challenging part but U can make it and will have a great sense of accomplishment when you are Done..
(1) if u need help with the trig I will be glad to help
(2) 3 degree included means 1.5 degree per side on a lathe
(3) if I have explained way too much that U already Know I am sorry Just trying to help .

Good Luck
Tony